For a 0.8- m CMOS fabrication process: Vtn= 0.8 V, Vtp = 0.9 V, nCox = 90 A/V2, pCox = 30 A/V2, Cox = 1.9 fF/ m2, VA (n-channel devices) = 8L ( m), and |VA| (p-channel devices) = 12L ( m). Find the small-signal model parameters (gm, ro and gmb) for a PMOS transistor having W/L = 20 m/2 m and operating at ID = 100 A and |VSB| = 1V.

gm= 0.12mA/V, ro= 240 k , gmb = 0.048 mA/V

gm= 0.24mA/V, ro= 240 k , gmb = 0.024 mA/V

gm= 0.24mA/V, ro= 120 k , gmb = 0.048 mA/V

gm= 0.24mA/V, ro=240 k , gmb = 0.048 mA/V

gm= 0.12mA/V, ro= 240 k , gmb = 0.048 mA/V

For a 0.8- m CMOS fabrication process: Vtn= 0.8 V, Vtp = 0.9 V, nCox = 90 A/V2, pCox = 30 A/V2, Cox = 1.9 fF/ m2, VA (n-channel devices) = 8L ( m), and |VA| (p-channel devices) = 12L ( m). Find the small-signal model parameters (gm, ro and gmb) for an NMOS transistor having W/L = 20 m/2 m and operating at ID = 100 A and |VSB| = 1V.

gm= 0.21mA/V, ro= 160 k , gmb= 0.042 mA/V

gm= 0.42mA/V, ro= 160 k , gmb = 0.084 mA/V

gm= 0.21mA/V, ro= 160 k , gmb= 0.042 mA/V

gm= 0.42mA/V, ro= 80 k , gmb = 0.042 mA/V

gm= 0.24mA/V, ro= 80 k , gmb = 0.084 mA/V

An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. Using a dc supply of 3 V, what values of ID and VOV would you choose?

0.34 mA and 0.35 V respectively

0.34 mA and 0.69 V respectively

0.034 mA and 0.35 V respectively

0.034 mA and 0.69 V respectively

Consider an NMOS transistor having kn= 2 mA/V2. Let the transistor be biased at VOV = 1V. For operation in saturation, what dc bias current ID results? If a +0.1-V signal is superimposed on VGS, find the corresponding increment in collector current by evaluating the total collector current ID and subtracting the dc bias current ID.

ID = 1mA and Increment = 0.42 mA

ID = 1mA and Increment = 0.21 mA

ID = 1mA and Increment = 0.42 mA

ID = 2mA and Increment = 0.21 mA

ID = 2mA and Increment = 0.42 mA

10 + Mcqs in MOSFET in Small Signal Operation Page 1 McqOptions

1.	The overdrive voltage at which each device must be operating is
A.	NMOS = 0.83V and PMOS = 0.48V
B.	NMOS = 0.48V and PMOS = 0.83V
C.	NMOS = 0.24V and PMOS = 0.41V
D.	NMOS = 0.41V and PMOS = 0.24V
Answer» C. NMOS = 0.24V and PMOS = 0.41V

Discussion

2.	For a 0.8- m CMOS fabrication process: V_tn= 0.8 V, V_tp = 0.9 V, _nC_ox = 90 A/V², _pC_ox= 30 A/V², Cox = 1.9 fF/ m2, V_A (n-channel devices) = 8L ( m), and \|V_A\| (p-channel devices) = 12L ( m). Find the small-signal model parameters (g_m, r_o and g_mb) for a PMOS transistor having W/L = 20 m/2 m and operating at I_D = 100 A and \|V_SB\| = 1V.
A.	g<sub>m</sub>= 0.24mA/V, r<sub>o</sub>= 240 k , g<sub>mb</sub> = 0.024 mA/V
B.	g<sub>m</sub>= 0.24mA/V, r<sub>o</sub>= 120 k , g<sub>mb</sub> = 0.048 mA/V
C.	g<sub>m</sub>= 0.24mA/V, r<sub>o</sub>=240 k , g<sub>mb</sub> = 0.048 mA/V
D.	g<sub>m</sub>= 0.12mA/V, r<sub>o</sub>= 240 k , g<sub>mb</sub> = 0.048 mA/V
Answer» D. g<sub>m</sub>= 0.12mA/V, r<sub>o</sub>= 240 k , g<sub>mb</sub> = 0.048 mA/V

Discussion

3.	For a 0.8- m CMOS fabrication process: V_tn= 0.8 V, V_tp = 0.9 V, _nC_ox = 90 A/V², _pC_ox= 30 A/V², Cox = 1.9 fF/ m2, V_A (n-channel devices) = 8L ( m), and \|V_A\| (p-channel devices) = 12L ( m). Find the small-signal model parameters (g_m, r_o and g_mb) for an NMOS transistor having W/L = 20 m/2 m and operating at I_D = 100 A and \|V_SB\| = 1V.
A.	g<sub>m</sub>= 0.42mA/V, r<sub>o</sub>= 160 k , g<sub>mb</sub> = 0.084 mA/V
B.	g<sub>m</sub>= 0.21mA/V, r<sub>o</sub>= 160 k , g<sub>mb</sub>= 0.042 mA/V
C.	g<sub>m</sub>= 0.42mA/V, r<sub>o</sub>= 80 k , g<sub>mb</sub> = 0.042 mA/V
D.	g<sub>m</sub>= 0.24mA/V, r<sub>o</sub>= 80 k , g<sub>mb</sub> = 0.084 mA/V
Answer» B. g<sub>m</sub>= 0.21mA/V, r<sub>o</sub>= 160 k , g<sub>mb</sub>= 0.042 mA/V

Discussion

4.	An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. What W/L ratio is required if _nC_ox = 200 A/V²?
A.	1.23
B.	1.23
C.	1.43
D.	1.53
Answer» D. 1.53

Discussion

5.	An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. Using a dc supply of 3 V, what values of I_D and V_OV would you choose?
A.	0.34 mA and 0.35 V respectively
B.	0.34 mA and 0.69 V respectively
C.	0.034 mA and 0.35 V respectively
D.	0.034 mA and 0.69 V respectively
Answer» E.

Discussion

6.	An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. If a gain of at least 5 V/V is needed, what value of g_m is required?
A.	0.1 mA/V
B.	0.2 mA/V
C.	0.4 mA/V
D.	0.8 mA/V
Answer» B. 0.2 mA/V

Discussion

7.	If in a particular application V_gs is 10 mV, find the minimum overdrive voltage at which the transistor should be operated so that the second-harmonic distortion is kept to less than 1%.
A.	1V
B.	0.75V
C.	0.5V
D.	0.25V
Answer» E.

Discussion

8.	We know I_D =1/2 k_n (V_GS + v_gs V_t)². Let the signal v_gs be a sine wave with amplitude V_gs, and substitute v_gs = V_gs sin t in Eq.(5.43). Using the trigonometric identity show that the ratio of the signal at frequency 2 to that at frequency , expressed as a percentage (known as the second-harmonic distortion) is
A.	V<sub>gs</sub>/V<sub>ov</sub> x 100%
B.	1/2V<sub>gs</sub>/V<sub>ov</sub> x 100%
C.	1/4V<sub>gs</sub>/V<sub>ov</sub> x 100%
D.	1/8V<sub>gs</sub>/V<sub>ov</sub> x 100%
Answer» D. 1/8V<sub>gs</sub>/V<sub>ov</sub> x 100%

Discussion

9.	Consider an NMOS transistor having k_n= 2 mA/V². Let the transistor be biased at V_OV = 1V. For operation in saturation, what dc bias current I_D results? If a +0.1-V signal is superimposed on V_GS, find the corresponding increment in collector current by evaluating the total collector current I_D and subtracting the dc bias current I_D.
A.	I<sub>D</sub> = 1mA and Increment = 0.21 mA
B.	I<sub>D</sub> = 1mA and Increment = 0.42 mA
C.	I<sub>D</sub> = 2mA and Increment = 0.21 mA
D.	I<sub>D</sub> = 2mA and Increment = 0.42 mA
Answer» B. I<sub>D</sub> = 1mA and Increment = 0.42 mA

Discussion

10.	An NMOS technology has _nC_ox = 50 A/V² and V_t = 0.7 V. For a transistor with L = 1 m, find the value of W that results in g_m 1mA/V at I_D = 0.5 mA.
A.	10 m
B.	20 m
C.	30 m
D.	40 m
Answer» C. 30 m

Discussion

Explore topic-wise MCQs in Electronic Devices and Circuits.

The overdrive voltage at which each device must be operating is

An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. What W/L ratio is required if nCox = 200 A/V2?

An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. Using a dc supply of 3 V, what values of ID and VOV would you choose?

An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. If a gain of at least 5 V/V is needed, what value of gm is required?

If in a particular application Vgs is 10 mV, find the minimum overdrive voltage at which the transistor should be operated so that the second-harmonic distortion is kept to less than 1%.

An NMOS technology has nCox = 50 A/V2 and Vt = 0.7 V. For a transistor with L = 1 m, find the value of W that results in gm 1mA/V at ID = 0.5 mA.

An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. What W/L ratio is required if _nC_ox = 200 A/V²?

An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. Using a dc supply of 3 V, what values of I_D and V_OV would you choose?

An NMOS amplifier is to be designed to provide a 0.50-V peak output signal across a 50-k load that can be used as a drain resistor. If a gain of at least 5 V/V is needed, what value of g_m is required?

If in a particular application V_gs is 10 mV, find the minimum overdrive voltage at which the transistor should be operated so that the second-harmonic distortion is kept to less than 1%.

An NMOS technology has _nC_ox = 50 A/V² and V_t = 0.7 V. For a transistor with L = 1 m, find the value of W that results in g_m 1mA/V at I_D = 0.5 mA.